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Mechanism of Bacterial P450 Catalyzed Pyrroloindole Skeleton Revealed

December 09, 2020      Author:

Recently, Professor Qu Xudong from the School of Life Sciences and Technology of Shanghai Jiao Tong University (SLST, SJTU), in collaboration with Dr. Jia Xinying and Professor Bostjan Kobe of the University of Queensland, Australia, published their research"Molecular Basis of Regio- and Stereo-Specificity in Biosynthesis of Bacterial Heterodimeric" on the website of Nature Communications, a top international journal. It is a new and important breakthrough in the field of pyrroloindole skeleton biosynthesis made by Prof. Qu Xudong's group. Prof. Qu Xudong, Dr. Xinying Jia and Prof. Bostjan Kobe are the co-corresponding authors of the paper. Sun Chenghai, postdoctoral researcher in SLST; and Luo Zhenyao, postdoctoral researcher from the University of Queensland, are the co-first authors of this article.

The heterodimerized pyrroloindole alkaloids derived from bacteria are a complex and important natural product with diverse biological activities. The chemical synthesis of such alkaloids is extremely difficult, and there is no unified and efficient chemical synthesis method. In order to solve this bottleneck problem, the research team led by Prof. Qu has taken a different approach by using biological methods and achieved a series of results in the biosynthesis of this type of alkaloids.

This research systematically analyzes the molecular basis of the regio/stereoselective dimerization of cyclic dipeptide substrates catalyzed by bacterial P450, and lays a solid foundation for the later enzyme engineering and the realization of efficient synthesis and structural expansion of pyrroloindole alkaloids.

The research is supported by the National Natural Science Foundation of China, the Shanghai Super Postdoctoral Program and the National Key R&D Project.

ABSTRACT:

Bacterial heterodimeric tryptophan-containing diketopiperazines (HTDKPs) are a growing family of bioactive natural products. They are challenging to prepare by chemical routes due to the polycyclic and densely functionalized backbone. Through functional characterization and investigation, we herein identify a family of three related HTDKP-forming cytochrome P450s (NasbB, NasS1868 and NasF5053) and reveal four critical residues (Qln65, Ala86, Ser284 and Val288) that control their regio- and stereo-selectivity to generate diverse dimeric DKP frameworks. Engineering these residues can alter the specificities of the enzymes to produce diverse frameworks. Determining the crystal structures (1.70-1.47 Å) of NasF5053 (ligand-free and substrate-bound NasF5053 and its Q65I-A86G and S284A-V288A mutants) and molecular dynamics simulation finally elucidate the specificity-conferring mechanism of these residues. Our results provide a clear molecular and mechanistic basis into this family of HTDKP-forming P450s, laying a solid foundation for rapid access to the molecular diversity of HTDKP frameworks through rational engineering of the P450s.

 

Source: School of Life Science and Technology, SJTU